I'd run it. It looks like you have a limited slip diff in there from the double set of spline engagement.
Thought the same.
The factory Ford limited slip is really a POS!
It actually uses the first 1/4" of those splines to drive the whole axle.
That's where the failure normally happens. Some call it a broken axle, but it's really just stripped splines.
With an open rear, those splines would last much longer, because they have a full inch of engagement with the spider gears.
All the factory '77 trac loks I've seen are 4 pinion (4 spider gears). That is a big strength improvement over the earlier 2 spiders. The axles spline to the side gears, not spiders.
The vehicle is a 77 with a large bearing axle. Currently running a 302 and c4. Yes, it does have a limited slip differential from the factory. Ultimately, the vehicle will be mostly a street vehicle with some very light offloading. I've been upgrading little things here and there in an attempt to make it road worthy, although when I have some more time and money, the vehicle will likely undergo a frame off restoration. So, i'm stuck between making it roadworthy now and reusing parts that are not too worn, or shelving the whole project until I can afford to do everything once with upgraded components.
I was travelling from SOCAL to Transport OR and it died in Redding.
I pulled the rear driveline and drove to Toms (then Ted's 4X4) for a replacement third member and axle.
Toms saved my salmon trip!
Not to hijack the thread, but where in the heck is Transport, OR? Been here my whole life and never heard of it. That said, good job getting over the Siskiyou Pass in front wheel drive...that's a good reason to run a good front shaft IMO.